


Repopulation is Logical

by Stella_Notecor



Category: Star Trek: Alternate Original Series (Movies)
Genre: M/M, Mpreg
Language: English
Status: In-Progress
Published: 2018-01-22
Updated: 2018-06-01
Packaged: 2019-03-08 00:51:38
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 6,821
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13447020
Author URL: https://archiveofourown.org/users/Stella_Notecor/pseuds/Stella_Notecor
Summary: Spock does not wish to leave Starfleet, but there is an urgent need for all Vulcan citizens to aid in the repopulation effort. When his relationship with Nyota ends, he decides to carry his own child. He will be able to remain onboard the Enterprise and fulfill his duty as a Starfleet officer as well as his obligation as a Vulcan.Spock is surprised by Jim's logical offer to donate his own DNA so that the child may know both of its parents. He is more surprised by his illogical longing to have Jim become a true parent to his child... and a true partner to Spock.(Spock/Kirk, mpreg, multi-chapter, canon compliant through Star Trek Beyond)





	1. Chapter 1

**Author's Note:**

> Most of the Kirk/Spock Mpreg I've read (and written!) has had Jim as the "mother". I decided that I would like to try a fic from Spock's POV post-Beyond since he seemed so interested in the repopulation effort!
> 
> I've taken liberties with Vulcan anatomy in this fic. Hopefully they won't seem too impossible.
> 
> I'm also going to do my best not to "humanize" Spock too much. Though, I've been rewatching bits and pieces of all three movies to check canon info, and honestly? Spock is an emotional bastard. Especially when it comes to Kirk. (Straight face while kissing Uhura? Check. Straight face while arguing with Kirk? Nope. While watching Kirk die? Yeah, no. While rescuing Kirk from near death yet again? Hah!)
> 
> So, I hope you enjoy. I'm guessing the fic will be somewhere around 5-6 chapters and 20,000-25,000 words. I'll do my best to write fast. =)

Spock stared across the table at Nyota. He thought he knew her. Now he knew he did not.

“You do not want to bear children?”

She crossed her arms. “No. I don’t want to deal with the changes to my body, to have to give up on my career for weeks or months.”

“In the past, you stated that you want a family.” They had discussed this early in their relationship, shortly after the destruction of Vulcan. Neither had been ready to start a family then, but Nyota had assured him that she wanted children in the future.

“I would love to have a family, Spock. Someday. But not now. And not by getting pregnant.” She leaned forward, resting her arms on the table between them. Spock was grateful they were having this conversation in his quarters. He was not certain he could continue to maintain his emotional control.

“We can adopt, Spock. Or use a surrogate.” She sighed deeply. “I’m sorry I didn’t tell you before, but the older I get, the more sure I am that I don’t want to be pregnant.”

The letter in his inbox had asked for him to provide his genetic material to continue the repopulation of the Vulcan species, should he not wish to sire children of his own. He knew his status in the repopulation database was rare: unbonded, no children. Even his father had taken another bond mate last month when the Vulcan Science Academy published their report on the lack of population growth. Spock predicted he would become an older brother within the next year.

Spock could simply provide his DNA for a Vulcan couple to use through artificial insemination. He did not need to sire a child. And yet, when he read that missive, a deep longing had arisen inside him. A longing for a child of his own blood.

“When do you predict that you will be willing to parent a child?” He could accept Nyota’s disinterest in carrying a child. Surrogacy would be an acceptable alternative.

Her shoulders slumped. “I don’t know. Maybe when I’m thirty-five or so? I’d like to sign on for at least one more five-year mission, and I don’t want to drag kids around the galaxy…”

Nyota was currently twenty-nine. It would be another six years before she would even consider starting a family? “I have been asked to aid in the repopulation efforts of the Vulcan species. If you are not willing to assist me, I will have to find another to bear my child.”

Standing, Nyota glared down at him. “Fine. Go fuck someone else.”

He had not meant to imply he would commit infidelity. “I would locate a surrogate, not another partner.”

“You’d still be having a kid with someone who isn’t me.” Her hands clenched into fists at her sides. “I don’t know if I can handle that. I need some time, Spock.”

“Are you terminating our relationship?”

“For now… yes.” Her fists relaxed. “Forever? I don’t know.”

“As you wish.” Spock stood as well and offered Nyota his hand. “Shall I escort you to your quarters?”

She shook her head. “I’ll talk to you later. Goodnight, Spock.”

He let his hand fall to his side as she walked out.

“Goodnight, Nyota.”

* * *

 

Nyota’s attempt to return his mother’s necklace told Spock she had made her decision. The small kiss on the corner of his mouth was a goodbye.

Spock made the decision to leave Starfleet for New Vulcan after Nyota left him. The news that Ambassador Spock has died served as confirmation that he made the correct decision. The Ambassador had not contributed his DNA to the repopulation effort. He told Spock the decision should be his, as this was his universe.

Then he was on Altamid. Spock fought to stay alive because Ambassador Spock was dead, and if he died too, there would be no one to carry on his work. No one to carry on his mother’s DNA.

He survived. He saved Nyota. But there was a distance between them. Once she would have kissed him, held his hand as they ran for safety. Instead she pulled him along by the elbow and maintained a professional distance.

Spock watched as his collegues fought to save Yorktown, each other, _him_. He did not want to leave them.

He was prepared to raise a child, but as Jim put it, what would the crew do without him?

How could Spock leave Starfleet? And yet, how could he not?

* * *

 

After the mission to Altamid, Spock required surgery to fully heal. He awoke after surgery to Dr. McCoy’s irritated glare.

“You have no idea how close you came to dying. Luckily all you punctured was your small intestine. Missed your heart by inches, and your vestigial uterus by centimeters. All those blood vessels… that would’ve been a mess.”

In a moment of blinding insight, Spock arrived upon a solution to his problem. “Doctor, am I healed enough for a revitalization of my uterus and ovaries?”

“A what?” McCoy gave him a wide-eyed glance. “The sedatives must not have worn off yet.”

Spock sat up in his biobed. “I would like to have my uterus revitalized. It is a procedure in which the vestigial organ is exposed to stem cells programmed to complete its development.” There had been much literature published on how to complete the procedure, which had been developed nearly two hundred years ago. While most Vulcans never needed to use their vestigial reproductive organs, it had been logical to develop the procedure for the few Vulcans who were transgender. “While most Vulcans undergo the procedure as a child during gender transitioning, it is my understanding that the stem cells may be administered to adults.”

McCoy pursed his lips. “Is this about that Vulcan baby thing? Because I gotta tell ya, I don’t think Uhura’s ready for you to go popping out kids.” He pinched the bridge of his nose. “Lord knows I’m not ready to see that.”

Spock clasped his hands in his lap. “I will be utilizing donor DNA. Lieutenant Uhura and I will not be reengaging in a relationship.”

McCoy pushed at his shoulder, forcing Spock to lay back. “Think about what you’re saying, man. You want to become a woman just to have kids? Can’t you adopt?”

He could. However, he did not want to. He wished to be a part of his child’s life from the point of conception. “I will not need to become a woman, Doctor. While it is true that the procedure will suppress my testosterone levels for a period of time, once I have given birth I will be able to have the uterus and ovaries removed. My body will then revert to that of a mature male.”

“You’re high on painkillers, Spock.” He pulled the blanket up from Spock’s waist and tucked it around his shoulders. “We can discuss this when you’re fully healed.”

“And how long will that take?”

“Three or four days; a week at the most.” McCoy snorted. “All that green blood is good for something, at least.”

A week would pass quickly. Spock would use that time to gather the pertinent data with which to convince McCoy to complete the procedure. Additionally, he would need to research the regulations regarding children on starships. To his knowledge he would be able to keep his child with him, but he would not request fertilization until he was certain.

Mind spinning, Spock lay in the biobed and watched the doctors and nurses work around him. He had much to prepare, and very little time in which to plan.

* * *

 

After being released from the medbay the next day, Spock attempted to complete his mission report. He found his mind kept wandering to his friends. They were preparing a surprise celebration for Captain Kirk’s birthday. Nyota had invited him to join her, but he had turned her down.

Upon deliberation, he determined that he wanted to see her. They may no longer be romantically involved, but he still considered her a friend.

He slipped into the party shortly before Jim was due to arrive. A drink was thrust into his hand.

“Thank you, Mr. Scott.”

Scott grinned. “No problem, Spock. And it’s zero-proof, sir. I dinnae want to mess with any of your medications.”

Spock doubted an alcoholic beverage would interfere with the mild pain relievers he had been prescribed, but he appreciated the lieutenant’s consideration.

Spock approached Nyota. As he reached her side, the Captain entered the room. Spock joined his crewmates in wishing Jim a happy birthday. At the end of Jim’s short speech, Spock gestured towards Nyota in toast.

She returned the motion. “I thought you had to finish your mission report.” Her right hand fingered his mother’s necklace.

“I do. But I thought it would be more pleasing to engage with you socially.”

“You old romantic.”

Spock caught McCoy’s eye then. He could almost hear the Doctor saying “See, you don’t need a uterus.”

But Spock knew Nyota better than McCoy did. Her words referred to him acting in an impractical manner, not a loving one.

“I will not be leaving Starfleet.”

Nyota tilted her head to the side. “You changed your mind?”

“No.” Spock swallowed the sweet liquid in his glass. “I will be bearing my own child.”

The look on Nyota’s face was nearly comical. “What?”

“Vulcans are born with male and female reproductive organs. At the age of seven, we begin to mature sexually, and one set of organs takes precedence over the other. The secondary set is then considered to be vestigial; however, there is a medical procedure which will allow the organs to develop.”

Nyota’s hand settled on his arm. “You’re going to become a woman? That doesn’t sound like you, Spock.”

If he lived in another time and place, Spock doubted he would ever undergo the procedure. But he lived in a universe where Vulcan had been destroyed and his mother had died. “It will only be temporary,” he attempted to assure her. “I will be able to return to my normal state of being after the child is born.”

Nyota frowned. Her hand tightened on his arm. “Why not use a surrogate? It will still be your baby.”

“I find that… I want to carry the child.” He could quote statistics on the current lack of Vulcan women available to become surrogates, on the difficulty of using a cross-species surrogate, on the chances of a Vulcan infant removed from its carrier having difficulty bonding, but in truth, his decision had been based on emotions, not logic.

“Oh, Spock…” Tears formed in Nyota’s eyes. “I’m sorry I couldn’t do this for you.”

“There is no need for apologies. I find this to be a suitable course of action.”

She sniffled and squeezed his arm once again before releasing him. “Can I get you another drink?”

“That would be acceptable.” He handed her his empty glass.

Nyota departed, and Jim sidled up to his table.

“I heard about Ambassador Spock.” Spock heard the shared grief in his voice. “Is that what you wanted to mention that time in the turbolift?”

“More or less.” While Spock had planned to discuss his intent to move to New Vulcan, that was no longer a necessary conversation. “I trust your meeting with Commodore Paris went well?” He had received a missive stating the Enterprise’s crew would be transferred to the new ship being built at Yorktown. He assumed Jim’s meeting had pertained to their new assignment.

“More or less.”

They stood together in shared silence.

Should Spock have departed Starfleet, he would have had to leave Jim and Nyota. With Ambassador Spock gone and his father busy with his work and new wife, Spock would have no one with whom to engage socially on New Vulcan.

“You really wanna head back out there, huh?” McCoy grumbled behind them.

Indeed, Spock would even have missed the surly doctor.

Uhura returned then, with a glass of cider for him. Looking out of the large window at the new ship, with his closest friends at his side, Spock knew he had made the right decision.

He would give birth to his child aboard the Enterprise-A with his Starfleet family to support him.


	2. Chapter 2

Spock perched on the edge of the biobed, waiting for McCoy to complete his review of the test results.

At last the doctor sighed and lowered his PADD. “Well, despite my best efforts, I can’t find a thing wrong with you. You’ll be back on active duty tomorrow.”

“Have you had a chance to review the literature I sent you?”

Spock had researched the revitalization in depth over the past week, and he was more certain than ever that he wished to go through with the procedure.

McCoy pursed his lips. “I read it. And I still don’t get it. Why become a woman when you can use a surrogate?”

Spock knew he would likely face the same question many times over the course of his transition and pregnancy. At least McCoy was asking out of concern and not disgust.

“Vulcan embryos begin to make a mental connection with their carrier at twelve weeks gestation. At twenty weeks gestation, the embryo is able to link to the carrier’s connections with their bond-mate and other family members. As I am not currently engaged in a relationship, I wish to carry my own child so as to ensure that we develop a strong familial bond.”

“Pull the other one, Spock.” McCoy crossed his arms, the PADD hanging forgotten in one hand.

“To which ‘other’ do you refer?”

McCoy groaned. “I mean, what’s the real reason you’re doing this?”

Gripping the edge of the biobed, Spock fought back his urge to speak in terms of logic. Dr. McCoy was looking for the feelings involved in his decision. Though he had many, many logical reasons for his decision, he knew as well as the doctor that he had chosen this path out of emotion.

“Ambassador Spock recently passed away. I have no close human relations. I wish to bear a child so as to ensure the continuation of my mother’s lineage.”

Face softening, McCoy’s arms fell to his side. “So, it’s about Human babies, not Vulcan ones.”

“Indeed.”

His father would surely pass on his DNA with his new bond-mate. There was little Spock could add to the Vulcan gene pool beyond what his father could also provide. Should he choose not to sire a child, however, his mother’s genetic material would go no farther than him.

“Then I’ll start the procedure now.” He poked Spock’s chest. “Provided you completely understand the process.”

Spock had, of course, memorized what would happen to his body. “The procedure consists of a series of injections containing stem cells, hormones, and hormone-suppressants. Over the course of three months, my penis will shrink and the skin covering my latent vaginal channel will thin until it becomes an external opening. Internally, my testicles will stop producing testosterone due to the hormone-blockers, and my sperm count will decrease. My uterus will grow in preparation for a potential pregnancy. My ovaries will begin to produce eggs at the three-month mark, at which point I will be able to conceive and gestate. I will continue to require hormone injections throughout the course of the pregnancy.”

McCoy didn’t look impressed. “And the risks?”

“The vaginal opening may not naturally occur, in which case I will require surgery. The ovaries may not begin to produce eggs, in which case I will require you to genetically manipulate my sperm to create an artificial egg. The uterus may never reach a viable size, in which case I will not be able to carry a child to term.” The last possibility occurred in 14% of Vulcans who transitioned as adults, but Spock calculated that his human DNA would increase the probability to 38%. It was statistically probable that the procedure would be futile, but Spock wished to proceed despite the odds.

McCoy nodded along as Spock spoke, but when he paused, McCoy frowned. “And what about afterwards?”

The possibility for complications was even higher after reversing the procedure, as it had been developed for transgender Vulcans to spend the remainder of their lives in their new gender. Reversing the change would require more injections and surgery. “Post-pregnancy, the penis may never return to its original size or sensitivity. The testicles may cease testosterone production fully, in which case I will require hormone injections for the remainder of my life. The loss of testosterone may cease production of sperm entirely, rendering me sterile. Pregnancy complications may result in continued complications with blood pressure, hormones, and/or autonomic regulation. The loss of autonomic regulation may lead to—“

McCoy held up his hand. “Alright, alright. You’ve done your research. Even will all the complications, you want to go through with this?”

“Indeed.”

“Fine.” With a sigh, McCoy turned on his heel. “I’ll be right back with the first injection. Crazy Vulcan.”

* * *

 

Spock accompanied Jim as they surveyed the Enterprise-A. In the month since their arrival at Yorktown, the new ship’s external shell had been completed. Life support had been completed the day before, and they were able to move about the internal portion of the ship without spacesuits.

Jim knocked on a bulkhead. The sound echoed through the empty corridor. “She sounds dead.”

“The ship is an inanimate object, Captain. It cannot be deceased as it was never living.”

“I know but…” Jim gestured at an opened door. “These are the crew quarters. There should be people running around, sleeping, eating… We don’t even have furniture yet!”

Spock glanced into the nearest room. Walls had yet to be constructed to separate the different sets of quarters. Pipes and wires protruded from the walls where the shared bathrooms would be built. “The engineering department will require 29.3 days to complete the quarters prior to the installation of furniture.”

“Spock…” Jim rolled his eyes. “Imagine what it will look like when our crew is here. Chekov fighting with his latest girlfriend. Scotty singing Scottish drinking songs at the top of his lungs. Sulu chasing his little girl down the corridor when she visits.”

Spock could easily extrapolate the images Jim wished him to perceive. However, instead of Lieutenant Sulu walking through the corridor with his daughter, a different image occurred to Spock. He would one day pass through this corridor with his own child.

An unbidden smile curved his lips. “Your point is well-made.”

Jim stared at him. “Whoa. Spock. You’re smiling.”

Spock quelled the facial expression. “My emotional control is currently 27% lower due to an ongoing medical procedure.”

“What’s wrong?” Jim’s hand gripped his arm. “Bones said you were fully healed.”

“The injury I sustained on Altamid has healed without issue.” Certain that Jim would not cease questioning him until Spock provided a complete answer, he continued, “The procedure is a gender transition.”

Jim’s eyes widened and his mouth fell open. “What?”

“I am transitioning from male to female so that I may carry a child.”

Jim continued to gape at him. He appeared unable to speak. Spock had never seen his captain as a loss for words before. Another smile made it through his controls at the fact that he had rendered Jim Kirk speechless.

Seeing his smile brought Jim out of his shock. “You want to get pregnant?”

“I wish to contribute to the Vulcan repopulation effort.”

“By becoming a woman?” Jim shook his head slowly, but finally released Spock’s arm. “That’s insane. Why didn’t you tell me about this before?”

“I do not intend to allow my medical needs nor the needs of my child to interfere with my duties.”

Jim leaned back against the wall and crossed his arms over his chest. “When are you due?”

“I am not currently expecting. I require another 10 weeks of treatment before I will be able to conceive.” At this point, not much had changed in Spock’s body. His penis had decreased in size by 6% and his body fat had increased by 3.5%. Internal scans had shown that his uterus had increased in size by 8%, but his ovaries were not yet producing hormones or egg follicles. There was still much progress to be made.

“Wait. What about Uhura?”

“Lieutenant Uhura and I terminated our romantic relationship prior to our mission to Altamid.”

“Damn… I thought you guys were gonna be together forever.” Jim’s arms fell to his side. “If even you two can’t make it work, I guess I’m doomed.”

“Doomed to what, Captain?”

Jim’s responding smile made an odd juxtaposition to his answer. “Loneliness, Mr. Spock.”

“As there will be four hundred and seventy-two crew members aboard the Enterprise-A, I do not believe you will lack potential companions.”

Jim shoved his shoulder. “Are you calling me a slut?”

Spock clasped his hands behind his back. “Certainly not. I merely wished to assure you that you do not lack for conversational partners. Also, I do not believe you meet the criteria to be termed ‘a slut.’ Based on my observations, you have engaged in sexual relations with three people over the past year.”

“Oh. My. God.” Jim turned away and started down the hallway.

“Captain?” Spock proceeded after him.

“Do you seriously keep track of the people I sleep with?”

“It is my understanding that humans perform their duties best when their emotions are stable. I have noted that your command decisions are the least rational in the three days following the termination of a sexual relationship. I monitor the status of your intimate relationships so that I can provide the appropriate level of command support during those periods of emotional compromise.”

Jim stopped in the middle of the hallway. Spock halted within centimeters of him, narrowly avoiding a collision.

“Captain?”

Jim turned slightly, his shoulder brushing against Spock’s chest. Due to Jim’s shorter stature, he had to raise his chin slightly to meet Spock’s gaze. “Is that the only reason?”

Spock had also found that Jim struggled personally at the end of his romantic relationships. “Due to your emotional discontent, I also attempt to provide personal support.”

Jim’s eyes didn’t leave his. “So that’s why you kept offering to spar or play chess with me?”

“Affirmative.” Spock took a small step backwards and clasped his hands behind his back. “To my knowledge, those are acceptable activities to engage in with a friend.”

“A friend…” Jim looked away, his gaze settling on something over Spock’s left shoulder. “Oh, Spock. What would I do without you?”

Spock had not heard Jim utter that phrase since he and McCoy rescued him from being sucked into space. He knew the answer. “You would die, Jim.” It was one of the many reasons that it was logical for Spock to remain in Starfleet.

"Yeah... I would." Jim turned away again. “Come on, Spock. Let’s go check out Engineering.” He chuckled. “And please… never tell anyone you’re keeping track of my sex life. Especially Bones.”

As Spock had no plans to share that knowledge, it was simple to respond, “As you wish.”


	3. Chapter 3

With many final decisions to be made regarding the Enterprise-A, Spock didn’t speak to Jim privately for another nine days. Finally, after a working dinner with Scott and McCoy, Jim invited him to his temporary residence for a game of chess.

Spock accepted the invitation, with the condition that he would not be partaking in alcohol. Dr. McCoy had advised against eating or drinking anything that could affect a growing embryo, based on the fact that Spock’s half-Human and half-Vulcan body might react to transitioning and pregnancy in unpredictable ways. Though Spock felt it was far too early to worry about such things, "Better to be safe than sorry," the doctor had proclaimed.

While Spock knew that the half-life of alcohol made it unlikely that a single drink would affect his treatment, he would follow the doctor’s orders. McCoy still exclaimed over his decision to go through with the transition after every injection. He had even threatened to end the treatment at the first sign of medical distress. Spock had no wish to provide further ammunition to fuel his negative biases. Thankfully, Jim had simply stated that his replicator was fully programmed and left it at that.

Jim had been placed in a separate hotel from Spock and the rest of the crew, ostensibly due to a lack of room in that building. Spock believed it was more likely due to Yorktown’s gratitude for his leadership during Krall’s attack and his personal risks that saved the entire starbase. Jim’s hotel was exceedingly luxurious, with plush carpeting and glimmering mirrors decorating the entrance. The glass-walled elevator allowed them to see out across Yorktown as it rose to one of the highest floors.

After a short walk down another heavily decorated hallway, Jim stopped in front of a door. After entering his keycode, they stepped inside.

Jim gestured to a small dining table on the opposite end of the room from the bed. “I refused a suite, so we’ll have to make due. I’ll replicate a chess set. What do you want to drink?”

“Tomato juice would bolster my potassium levels.”

“Then tomato juice it is.”

They settled into their seats, Jim with a glass of whisky and Spock with his tomato juice. The simple chess board covered most of the square tabletop. Jim maneuvered the board a bit so that they had room for their glasses on the table, then rearranged himself in his seat. Under the table, their knees bumped together. Jim looked somewhat awkward slumped down into his chair, but he smiled across the table at Spock. After he ceased moving, Spock slid his legs to one side to provide room for Jim’s new position.

Jim’s smile disappeared. He sighed and straightened up in his chair.

“So, what’s new in your life, Spock?” He made the first move, sliding a white pawn forward.

“The science labs have progressed to 83.5% completion aboard the Enterprise-A. As the physical structure has been nearly completed, computer and laboratory equipment is being installed as we speak.”

“No, what’s new with _you_? Like, how is your transition going?”

Unsurprised that Jim had approached such personal matters within the first few minutes of conversation, Spock shared an update on his physical state.

“As of two days ago, 29.34% of the necessary physical changes have already occurred in my body. External changes have been the most distinct. While I have no plans to change my outward style of dress, I will soon need to utilize more feminine undergarments.”

Jim’s eyes flickered down to Spock’s chest and then back up. “You’re growing boobs?”

“Indeed.” While Dr. McCoy had assured Spock that his breasts were unlikely to develop much in size, the fat deposits surrounding his nipples had increased. Additionally, he found the nipples themselves to be quite sensitive. He assumed that a bra would alleviate the sensation of his clothing sliding across his chest.

“Shit.” Jim frowned at the board as Spock slid one of his pawns forward. “You really are turning into a girl.”

“As I am thirty-three years of age, the term woman is more accurate.” Spock watched Jim carefully slide another pawn out of line. “However, while my physical sex will be temporarily altered, I still consider my gender to be male.” Spock considered his knights for a moment before selecting a pawn to move.

“Oh, thank god.” Jim grinned. “I was afraid this was a permanent thing.”

“No, I plan to re-transition to a male body after giving birth.”

Jim leaned forward and propped his elbows on the table. Holding his face in his hands, he fixed his gaze on Spock. His position jostled the chess board, knocking over some of the pieces. “Why go through all of this for a kid?”

Apparently chess was merely an excuse to inquire more about Spock’s treatment. While Jim’s interest could be considered intrusive, Spock felt that his friend merely wanted to ascertain an understanding of the situation. He had already shared his reasoning with McCoy, but somehow, sharing his emotional reasoning with Jim was harder.

“I wish to pass on my genetic code; Vulcan… and Human.”

Jim’s eyes softened. “You mean, your mom’s DNA.”

“I… yes.”

Jim’s gaze drifted over Spock’s shoulder. “Are you going to have a girl then?”

Spock hadn’t considered gender selection. A daughter might remind him of his mother, but a son could just as easily portray the same genetic traits. “I will produce an egg to be fertilized in utero. The gender will be determined by the donor sperm.”

“Donor sperm?” Focusing on him, Jim leaned forward, his arms crossing on the table and knocking over more of the chess pieces. “Not your own?”

Spock quirked his eyebrow at Jim. “Certainly not. Repetition of my own genetic sequences could result in abnormalities.” Using his own sperm would be tantamount to creating a child through incest. “The only way to ensure a healthy embryo would result from only the use of my DNA would be to create a clone. I will procure sperm from the Vulcan Genetic Bank.”

“Aw…” Jim chewed on his lower lip. “Your mom’s going to get buried under Vulcan logic.”

If Spock used Vulcan sperm, his child would be approximately 75% Vulcan. He or she would be even less likely to embrace his or her humanity than Spock. Unlike Spock, the child would likely not bear his mother’s brown eyes or distinctive nose or thin lips.

“Perhaps I should attempt to procure sperm from a Human donor.” While Vulcan DNA would still be dominant, his mother’s genetic code would surely be more predominant in that case.

Jim’s face lit up. “You can use mine!”

Spock could not keep his eyebrows from rising on his face. His friend had never expressed an interest in having children. “While I appreciate the offer, Captain, you may wish to consider the decision more thoroughly.”

Jim flapped his hand at him. “No, listen, it’s perfect! We’ve got two more years left on our mission, right? But after that, Command will probably want us to split up.” He crossed his arms over his chest. “You said it yourself, Spock. Without you, I’d be dead. And you know, without me, you’d be dead too. Splitting up would be stupid. But if we do this, have a kid together, they’ll have to let us stay together!”

“Sperm donation does not require active involvement of the donor in the child’s life.”

“Well, then, I won’t donate it. Not formally. You can put me on the birth certificate. On paper, the kid will be related to both of us.” Jim nodded his head as if certain he had all the answers.

Jim was intelligent. Aside from his allergies, he was in good physical health. His genetic code would certainly blend with Spock’s to create a well-formed embryo. Additionally, his blue eyes and light brown hair were recessive traits compared to his mother’s brown eyes and dark brown hair. If the child inherited her physical features and not his father’s, they would easily predominate over Jim’s.

Spock had no logical reason to refute Jim’s offer. He also had no emotional reason. He found the idea of his child knowing both of his or her parents quite comforting, in fact. While Spock did not believe Jim held any interest in raising the child, having him in close proximity during the child’s formative years would enable the child to understand him or herself better.

A decision would require further contemplation. “I will consider your offer.”

Jim’s smile widened. “That’s nearly a yes from you, Spock.”

“Shall we continue our game?” Spock began to re-situate the chess pieces Jim had knocked over. They resumed their chess game and the evening continued as if it were simply another night of chess and conversation, like the many they had shared in the past.

And yet… every time Jim’s offer resurfaced in Spock’s mind, he felt a warm affection in the center of his chest. Spock appreciated that Jim supported his decision to such a degree.

Nyota had not been able to even consider supporting Spock’s wishes, but Jim had offered so easily. Was it because he had not fully considered the offer, or did he truly wish to remain with Spock that much? His friend had been willing to give his life to save others; giving his sperm probably felt inconsequential in comparison.

Nine weeks remained before Spock could consider becoming pregnant. He had much to consider in that time.


	4. Chapter 4

Spock almost changed his mind about the transition two weeks later when he woke up an hour before his alarm, covered in blood, with a deep ache in his pelvic region.

His first menstrual cycle had begun while he slept. He had not expected it to begin until after his ovaries began ovulating after 8 more weeks of treatment, but his human genes had likely contributed to the early initiation.

Grateful he did not have to launder his sheets and clothing, he stripped the bed and then himself. After throwing the soiled material down the laundry chute, he replicated a pair of underwear designed for menstruation. He gathered a uniform and a bra from his wardrobe, then stepped into the hotel bathroom.

After hanging his clothing on the provided hooks, he took a moment to observe himself in the mirror hanging on the back of the door. His breasts had swollen to the point where they obviously contained as much mammary tissue as muscle tissue. Additional fat had settled on his stomach and hips. He had already increased one pant size due to the change in fat distribution. Should it continue, he would likely need to change to the female uniform, as those pants were cut to fit wider hips than his own.

Between his legs, his penis still hung down, but it was noticeably smaller. His testicles were internal, so he didn’t have anything to hide the vagina that had begun forming behind his penis. The vaginal slit had still been covered with thin, sensitive skin when he had last observed it.

He took a seat on the edge of the toilet, as it stood opposite the mirror. Spreading his legs and lifting his penis out of the way, he found that the vaginal slit had split on its own. The hole that had formed was only 1.25 centimeters across at its widest point, but that was large enough for his bright green menstrual blood to escape. There wasn’t much, as his garments had absorbed most of what he had passed, but the green smears across his inner thighs made his stomach churn.

Spock clambered into the shower, nearly tripping over the lip of the tub in his haste. He turned the water on, desperate to remove the blood as quickly as possible. A sonic shower would not be enough to make him feel clean.

What was he doing? He had changed his whole body. The person who he saw in the mirror was not Spock.

As the warm water beat down on his skin, washing away the green traces, Spock took a deep breath. Then another. He was still himself. He had known that these changes would occur. Still more changes would occur over the remaining eight weeks of treatment.

Spock understood why the treatment was only recommended for transgender Vulcans. His body no longer felt like his own. He had often wondered why transgender individuals wanted to change their gender. Privately, he had often felt that they overstated how much their gender impacted their lives. Men and women were treated equally, able to do anything they wanted regardless of gender. Now he understood better how living in the wrong body could make one feel.

Facing his own feelings of dysphoria, he clasped a washcloth and wet it under the showerhead. Reminding himself that this was a temporary situation, but one which he would be dealing with for months, he steeled himself and pressed the washcloth between his legs.

The rough cloth stung as it tore the vaginal slit open more. Spock clenched his teeth against the pain. He would need to gently stretch the area until his slit was fully formed, unless he wanted to undergo surgery to open it. At least he would not need to undergo the surgery necessary to form labia, reroute his urethra, and transform his penis into a clitoris as a transgender adult Vulcan would if she wished to have fully female genitalia.

After spending a few moments dilating his vagina, Spock rinsed out the washcloth. There was very little blood on it. He expected this first menstruation would be short and light. If possible, he would attempt impregnation before the next cycle could begin.

Which meant he would need to decide whether or not to use Jim’s sperm soon.

Spock lathered a clean washcloth up with soap. He scrubbed himself methodically from head to toe in the order he had used since he was a child. Face, neck, shoulders, arms, chest…

At his chest, he paused. His nipples were so sensitive… the rough washcloth running across them sent a feeling like a bolt of lightning straight through his abdomen and between his legs.

He was going through all of these changes for the purpose of having a baby. His mother’s grandchild. His child. Jim’s child?

Five years ago, Jim had been reckless and careless. Spock would have turned him down immediately.

...his chest was certainly beyond clean, and the dull ache in his pelvis seemed to be spreading. Spock continued washing: abdomen, back, hips, buttocks, thighs… calves should be next, but as he ran the washcloth between his legs, the back of his hand pressed into his slit. The lightning returned, but now it seemed to shoot into his penis.

Spock had not planned to masturbate that morning. He typically indulged only three times a week, as a mental release on the days when he did not meditate. However… he had awoken an hour early.

He switched the washcloth to his non-dominant hand and resumed scrubbing his nipples. With his dominant hand he began to stroke his penis. While his male genitals had become less sensitive over the course of treatment, the sensations streaking through his body from his nipples more than made up for the difference. It would not take him long to achieve orgasm.

His hands continued moving without any focus, and Spock’s brain drifted back to Jim. He had not retracted his offer since he made it two weeks prior. Nor had he repeated the offer. Spock wondered if he had truly considered the consequences of becoming a father.

From Spock’s research, he knew that co-parenting pairs were given priority when making placement decisions. If they had a child together, Spock and Jim would not be separated unless they specifically requested it. And Spock could never see himself requesting a position away from Jim.

Jim was… his closest friend. Spock had never assigned that label to another person prior to meeting Jim. On Vulcan he had acquaintances, colleagues, and family members. When he arrived at Starfleet Academy, Spock had added lovers to that list. Pike, McCoy, Uhura... each of them had developed into friends over time. Uhura and he had grown quite close, but becoming lovers had paused the growth of their friendship, and spending the majority of their time focused on work had halted the growth completely. Perhaps that was why their relationship had ultimately failed.

Spock could not see his friendship with Jim failing. They had already faced so much together; Spock could not fathom what could end their relationship.

Aside from being forced apart.

His erection nearly wilted at that thought. Spock pushed it aside and increased the speed of his hands.

Having a child with Jim would insure a lifetime connection. Their connection would exceed their lifetimes, in fact, as their DNA would remain entwined in their child’s children, and their grandchildren’s children, and their great-grandchildren’s children…

So long as their lineage continued, a part of him would always be touching Jim. They could be parted and never part. Never and always touching and touched…

Spock’s orgasm caught him by surprise. It rippled through him oddly, seemingly centered deep in his pelvis instead of in his testicles. The dull ache inside him tightened and released soothingly. A single dollop of seminal fluid dripped from the head of his penis, as if an afterthought.

His body had processed the orgasm as if he were female.

Spock refused to let gender dysphoria overwhelm him again, so he took a deep breath, switched his washcloth back to his dominant hand, and resumed scrubbing his thighs. His body was nearly prepared for pregnancy, and so was his mind.

There was no one in the universe more suited to father Spock’s child than James T. Kirk.

**Notes for the Chapter:**

> Seems to me that Vulcans would treat masturbation as a tool to release oxytocin and what not. So I totally went with Spock not even thinking twice about masturbating while ~~dreaming~~ thinking about Jim.
> 
> Tried to use everything I've learned about gender dysphoria and being transgender appropriately in this chapter, but if you are transgender/know more about being transgender than me, feel free to critique my explanations!
> 
> I'm sorry for the delay in updates... I'm dealing with major health issues at the moment. However, I'm a teacher and have just started summer break, so I'm hoping for updates to resume their prior weekly speed. *crosses fingers*


End file.
